Multiple gear fluid pump



Jan. 11, 1955 A. F. ERICKSON MULTIPLE GEAR FLUID PUMP Filed May 27, 1952 R0 Q c E/ e W5 A N- m H/S ATTUQNE Ys.

United States Patent MULTIPLE GEAR FLUID PUMP Anton F. Erickson, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 27, 1952, Serial No. 290,291

7 Claims. (Cl. 103126) This invention relates to an improved fluid pump.

It is among the objects of the present invention to provide a fluid pump of the meshing gear type in which the volume of displaced fluid is substantially greater than the ordinary gear pump.

This is accomplished by providing a plurality of pinion gears meshing with and driven by a single driving gear, each pinion gear meshing with the driving gear providing an individual increment of fluid discharge to the complete volume of fluid discharged under pressure by the pump.

Another object of the present invention is to provide a multiple gear pump with a housing providing recesses in which the pinion gears are floatingly contained so that fluid under pressure within the housing will exert an outward thrust upon the several pinion gears thereby providing a pressure seal between the outer circumference of the respective pinion gears and the wall of the housing recesses in which the respective pinion gears are contained.

A still further object of the present invention is to provide a multiple gear pump capable of delivering a substantially constant fluid flow under pressure and without distinct pulsations.

By spacing the pinion gears at predetermined, unequal angles in a circular row about the common drving gear, out of phase fluid discharges, equal in number to the pinion gears provided, are obtained, such out of phase fluid pressure discharges resulting in a substantially constant flow, pulsations being practically eliminated by the merging of the several increments of fluid discharge to form the complete volume of fluid discharged by the um p Tli ese same results may also be obtained by providing pinion gears each having the same even number of teeth and meshing with a driving gear having an odd number of teeth. In this instance the pinion gears, all of identical size, are equal, angularly arranged in a circular row about the driving gear.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a side view of one pump construction embodying the present invention.

Fig. 2 is a plan view of the pump housing portion recessed to receive the multiple pinion gears and the driving gear meshing therewith.

Fig. 3 is one cover cap of the pump shown in Fig. 1, showing the several intake ports and connecting channels when the driving gear, shown in Fig. 2, rotates clockwise as indicated by the arrow.

Fig. 4 is a plan view of the other cover cap of the pump shown in Fig. 1, showing the severed fluid discharge ports and connecting channels.

Fig. 5 is a View similar to Fig. 2 showing a modified construction in which all pinion gears have an even number of teeth and the driving gear an uneven number of teeth.

Referring to the drawings the Fig. 1 illustrates one type of pump construction which has a body plate 20 sandwiched between two end plates 21 and 22. The plates sealingly engage opposite side surfaces of the body plate and the entire assembly is held clamped together by screw bolts 23. The end plate 21 has a central lug in which the drive shaft 24 is journalled, said shaft extending into a central recess 25 in the body plate 20 and having the driving gear 26 attached thereto. The recess 25 is circular and extends completely through the body plate 20 and is of a diameter so that the outer, peripheral surfaces of the teeth on gear 26 slidably engage the annular wall of the recess and provide for a fluid seal between the teeth and recess wall. The body plate has four identical, circular recesses 30, 31, 32, 33 passing completely through it, said recesses being arranged in a circular row concentric of the recess 25, each of these four recesses cutting into said central recess so that pinion gears 34, 35, 36 and 37, in said respective recesses 30, 31, 32 and 33, operatively mesh with gear 26 in recess 25. In the construction shown in Fig. 2, the gear 26 has 24 teeth and each pinion gear has 12 teeth. These teeth are so formed that as they operatively mesh, the tooth of one entering the space between the two adjacent teeth of another gear will fill said space as completely as possible. The annular wall of each recess containing a pinion gear slidably engages the outer, peripheral faces of the gear so that a fluid seal may be formed between the recess wall and its contained gear. All pinion gears float in their respective recesses so that fluid pressure in the fluid displacement chamber, formed by the recesses and the respective cover plates, urge and maintain said pinions toward the recess wall to provide a pressure seal between the respective pinion gears and the pump body. The cover plates engage the respective end surfaces of the pinion gears and the central driving gear.

Recesses 30, 31, 32 and 33 are unequally angularly spaced relatively to one another. In the present construction pinion gear 34 is spaced at an angle of substantially 79 /2 degrees from the pinion gear 35 and at an angle substantially 111 degrees from the other ad jacent pinion gear 37. Pinion gear 36 is spaced at an angle of substantially 83 degrees from the pinion gear 35 and at an angle of substantially 86 /2 degrees from the pinion gear 37. This particular spacing of the pinion gears assures against concurrent occupancy to the same degree of gear teeth of two pinion gears with gear tooth spaces on the gear 26. In other words, at no one time will a tooth of any two pinion gears fully occupy gear tooth spaces on the gear 26, but such full occupancy is successive at predetermined intervals due to such spacing of the pinion gears.

Fig. 3 is a flat view of the cover plate 21 attachable to the bottom side of the body plate 20 as shown in Fig. 2. This plate has four fluid inlet ports 40, 41, 42 and 43 extending from the inside flat surface of plate 21 partially through the plate. Fluid inlet passages 44, 45, 46 and 47, shown in dotted lines in Fig. 3, are formed in the plate 21 and extending from the outer peripheral surface of the plate partially through the plate. Passage 44 has its outer end closed by a screw plug and communicates with the inlet ports 40 and 41. Passage 45 receives the pipe 48 leading from any suitable fluid supply and communicates with inlet ports 41 and 42. Passage 46 is closel by a screw plug and communicates within inlet ports 42 and 43. Passage 47 is closed at its outer end by a screw plug and communicates with inlet ports 43 and 40. Thus all inlet ports 40, 41, 42 and 43 are in communication with each other and with the fluid supply pipe 48.

When the plate 21 is attached to the plate 20 as shown in Fig. 1, or to the bottom side of this plate as shown in Fig. 2, inlet port 49 communicates with the fluid displacement chamber containing the pinion gears and the driving gear adjacent the area of tooth demeshment of gears 34 and 26 generally designated by the numeral 50. Gear tooth demeshment will draw fluid from the inlet port 40 to fill a space between adjacent teeth of gear 26, vacated by a tooth of the pinion gear 34, and at the same time a space between teeth on pinion 34 at this area vacated by a tooth on gear 26 will be filled with fluid. Inlet port 41, open to the area adjacent the demeshment of gears 35 and 26, will supply fluid to fill spaces between adjacent teeth of gear 26 and pinion 35 at this area. Inlet port 42 supplies fluid in the same manner and for the same purpose at the area of demeshment of gears 36 and 26 and inlet port 43 performs the same function at the demeshment area of gears 37 and 26. Thus eight separate spaces between adjacent teeth of gear 26 and the pinion are currently loaded with a fluid supply such space loading being effected as the succeeding spaces are evacuated by meshing teeth.

As the gear 26 rotates, a supply of fluid is contained in each space between adjacent teeth of said gear 26 as well as the four mating pinions and as said spaces proceed from the demeshing areas of the respective pinion gears and driver gear toward the areas where said pinion gears start to engage the driver gear. When a tooth of a pinion gear starts to enter a space between teeth on the driver gear, as for instance the tooth 51 on the pinion gear 35 entering space 52 on gear 26, the fluid in said space, carried around from the intake port 40 area, will be displaced by tooth 51 and forced, under pressure, into the adjacent discharge port 60 provided in the cover plate 22. Meshing teeth on pinion gears 36, 37 and 30 will have the same fluid displacement effect and will progressively force fluid into the respective discharge ports 61, 62 and 63. Immediately thereafter the tooth on the gear 26 following cavity 52 will enter the cavity on the pinion 35 following tooth 51 and thus force the contents of this cavity into the discharge port 60. These discharge ports open in the surface of plate 22 engaging the body plate 20 and, like intake ports in plate 21, are interconnected by fluid passages 64, 65, 66 and 67 in plate 22. All of the passages excepting passage 67, are plugged at their outer ends, passage 67 having the fluid discharge pipe 68 of the pump connected thereto. Thus as each tooth of the respective pinion gears enters a space between adjacent teeth on the driver gear 26, and likewise as a tooth on the driver gear enters a cavity on the respective pinion gears a charge of fluid is forced, under pressure, into a discharge port adjacent the respective pinion gear. The fluid discharged into the four discharge ports 60, 61, 62 and 63 merges in the interconnected passages 64, 65, 66 and 67 and pass from the pump through the discharge pipe 68. These fluid displacements from the gear spaces on gear 26 and all pinions are not simultaneous, but due to the unequal, angular spacing of the pinion gears, each eight discharge impulses by the four pinion gears and driver gear are successive with a predetermined time interval between said impulses. This arrangement substantially reduces the magnitude of the fluid discharge impulses which would be considerable if all four pinions acted in unison to discharge the fluid content of four gear teeth spaces into the fluid discharge pipe at the same time. The volume of fluid displaced by a four pinion gear pump will be four times as much as the volume displaced by a pump having a single pinion gear operating with a driver gear. If more volume is desired, more pinions may be provided in a pump of this kind.

Impulse control may also be obtained by arranging four pinion gears in equal angular displacement around a driving gear, provided the four identical pinion gears have an even number of teeth and the driver gear, meshing with the pinion gears has an uneven number of teeth. This will eliminate concurrent fluid discharge impulses and provide the same even fluid discharge as the pump shown in Fig. 2 where the pinion gears are unequally angularly spaced about the driver gear. Fig. illustrates the gearing arrangement where pinions 134, 135, 136 and 137 are equal angularly spaced about the meshing driver gear 126.

The present invention thus provides a fluid pump of the gear type, simple in design and construction and capable of delivering greater volume of fluid under pressure than ordinary gear pumps of the same size. By its construction fluid discharge impulses are reduced to a minimum thereby assuring a substantially constant and even flow fluid discharge under pressure.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A fluid pump comprising, a casing providing a fluid displacement chamber in which a central gear meshes with a plurality of pinions floating relative to said gear, the wall of the displacement chamber being slidably engaged by the end faces of the teeth of said pinions and gear; a fluid inlet port means in the casing communicating with the displacement chamber adjacent the teeth demeshing area of each respective pinion and the gear; fluid discharge port means in the casing communicating with the displacement chamber adjacent the teeth meshing area of each respective pinion and the gear; and a drive shaft journalled in the casing drivingly connected to said gear.

2. A fluid pump comprising, a casing providing a fluid displacement chamber, said displacement chamber including a central, circular opening directly communicating with a plurality of circular openings arranged concentric of said central opening and predeterminately variably angularly spaced relative to each other; a gear slidably fitting in each one of said openings with the gears in the concentrically arranged openings operatively meshing with the gear in the central opening and free for floating radial and circumferential movement in their respective openings relative to the central gear; fluid inlet ports for each meshing pair of gears, fluid discharge ports for each meshing pair of gears and a drive shaft journalled in said casing and attached to said central gear.

3. A fluid pump consisting of a body having a main circular recess which communicates with a plurality of other circular recesses arranged about said main recess in a circular row concentric of said main recess so that said other recesses overlap and cut into the main recess, said other recesses being unequally spaced angularly; a power driven gear rotatably fitting into the main recess and meshing with pinions rotatably fitting into said other recesses and radially floating therein; a power driven shaft in the housing connected to said gear; fluid intake ports leading into said recesses adjacent the areas at which the respective pinions demesh with the driving gear, said intake ports communicating with a common fluid passage in the housing; a cover plate attachable to the housing for sealingly covering the gear and pinion recesses; fluid discharge ports in said cover plate leading into the recesses in the housing adjacent the areas at which the respective pinions mesh with the driving gear, said discharge ports being in communication with a common discharge passage in the cover plate.

4. A fluid pump consisting of four identical pinions each with an even number of teeth meshing with a single gear also having an even number of teeth, the angular displacement of the adjacent pinions being substantially 86 /2, 83, 79 /2 and in respective succession; said gear and said pinions thereby effecting intermeshing of teeth in a manner to cause discharge of fluid under pressure from the several pinions in a regular sequence with the discharge pulses separately and predeterminately timed relative to each other to prevent any concurrent pulsing discharge from any plurality of the pinions, a housing recessed to receive said pinions and gear, the contour of said recess being such as to provide a continuous wall contiguous to the faces of the pinions and gear so as to provide a sliding fit; a power shaft journalled in the housing and attached to the gear for rotating it; four intake ports in the housing each communicating with the gear containing recess adjacent an area where the teeth of the gear and a respective pinion unmesh and create a void; a common fluid intake passage in the housing communicating with all four intake ports; a sealing cover for the housing, providing a surface engaged by the ends of the pinions and gear, said cover having four discharge ports each communicating with the gear containing recess at an area where the teeth of the gear and a respective pinion mesh and displace fluid; and a common fluid discharge passage in the cover, communicating with all of said discharge ports, the varying angular relation of the pinions providing a substantially constant and nonpulsating fluid discharge.

5. A fluid pump having a housing providing a fluid displacement chamber in which a plurality of identical pinions are operatively engaged by a central driving gear, said pinions and gear having an even number of teeth, the pinions being unequally, angularly spaced about said gear in such a manner that, starting from the pinion one tooth of which is fully meshed with the gear, comparable teeth of the successive pinions are concurrently meshed at increasing fractions of full enmeshment, the denominator of said fractions being the sum of the pinions in the pump, the numerators being respectively the succession number of the pinions to complete its full displacement enmeshment with the gear; a shaft journalled in the housing and attached to the gear for rotating it; said gear and said pinions thereby effecting intermeshing of teeth in a manner to cause discharge of fluid under pressure from the several pinions in a regular sequence with the discharge pulses separately and predeterminately timed relative to each other to prevent any concurrent pulsing discharge from any plurality of the pinions, and fluid inlet and outlet ports in the housing, communicating with said displacement chamber at areas adjacent the pinion and gear teeth demeshment and enmeshment respectively.

6. A fluid pump having a housing providing a fluid displacement chamber in which a plurality of identical pinions are operatively engaged by a central driving gear; said pinions and gear having an even number of teeth, the pinions being unequally, angularly spaced about said gear in such manner that, fluid discharge impulses, double in number to the pinions in the pump and at substantially equal successive intervals for each revolution of the gear are provided by the pump; a drive shaft attached to said gear for rotating it; said gear and said pinions thereby eflecting intermeshing of teeth in a manner to cause discharge of fluid under pressure from the several pinions in a regular sequence with the discharge pulses separately and predeterminately timed relative to each other to prevent any concurrent pulsing discharge from any plurality of the pinions, and fluid inlet and outlet ports in the housing, the inlet ports communicating With the displacement chamber adjacent each area of disengagement of the respective pinions and gear, the outlet ports communicating with the displacement chamber adjacent each area of engagement of the respective pinion and gear.

7. A fluid pump comprising, a casing providing a fluid displacement chamber, said displacement chamber ineluding a central circular opening directly communicating with a plurality of identical circular openings arranged about said central opening and intersecting said central opening, a gear rotatably fitting Wtihin said central opening, an identical pinion in each of said plurality of circular openings in meshing engagement with said gear, said pinions being predeterminately variably angularly spaced relative to each other about said central opening whereby said gear and said pinions eflfect intermeshing of the teeth in a manner to cause discharge of fluid under pressure from the several pinions in a regular sequence with the discharge pulses separately and predeterminately timed relative to each other to prevent any concurrent pulsing discharge from any plurality of the pinions, fluid inlet port means in the casing communicating with the displacement chamber adjacent the teeth demeshing area of each respective pinion and the gear, and fluid discharge port means in the casing communicating With the displacement chamber adjacent the teeth meshing area of each respective pinion and the gear.

References Cited in the file of this patent UNITED STATES PATENTS 1,287,118 Shore Dec. 10, 1918 1,460,875 White July 3, 1923 1,585,731 Oakes May 25, 1926 1,719,693 Ernst July 2, 1929 1,870,824 Shepard, Jr. Aug. 9, 1932 2,329,230 Thomas Sept. 14, 1943 2,399,008 Doran Apr. 23, 1946 FOREIGN PATENTS 624,177 France Mar. 29, 1927 

